Wafer protection structure and wafer processing method

Abstract

The invention discloses a wafer protection structure and a wafer processing method, and the wafer protection structure comprises a reinforcing ring which is bonded on the upper surface of a wafer through a reinforcing ring curing adhesive, the shape and size of the outer edge of the reinforcing ring are the same as those of the outer edge of the wafer, the outer edge of the reinforcing ring is aligned with the outer edge of the wafer in the axial direction of the wafer, and the upper end face of the reinforcing ring is parallel to the upper surface of the wafer. The wafer protection structure according to the embodiment of the invention has the advantages that the wafer can be effectively prevented from being deformed and damaged, the yield of finished products is improved, and material waste and cost burden are reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer protection structure and a wafer processing method. Background Art

[0002] Wafer bonding and thinning technology is to bond the wafer and the carrier to form a bonded sheet through a cured adhesive, and then thin the wafer. With the development of bonding and thinning technology, large-sized wafers with thickness at the sub-micron level can be prepared.

[0003] The wafers in the related technology, especially the large-sized wafers after thinning, on the one hand, the crystal structure strength of the wafer itself is relatively fragile, and it is easily affected by external forces such as vibration and collision during transportation. Slight vibrations may also cause scratches or microcracks on the surface of the wafer. Moreover, the larger the size of the wafer, the greater its own weight and inertia, and the more likely it is to be damaged. On the other hand, it is inevitable that stress will be introduced into the wafer during the thinning process, which can easily cause the wafer to warp, reduce the wafer strength, and crack. In the subsequent processing of micro-nano devices, cracks are easily generated in the stress concentration area when subjected to slight external force impact or temperature changes. This leads to a low yield of finished wafers and greatly increases the material waste and cost burden in the production process. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a wafer protection structure, which can effectively prevent the wafer from being deformed and damaged, improve the yield of finished products, reduce material waste and cost burden, etc.

[0005] The invention also provides a wafer processing method.

[0006] To achieve the above-mentioned purpose, a wafer protection structure is proposed according to an embodiment of the first aspect of the present invention, and the wafer protection structure includes: a reinforcement ring, which is bonded to the upper surface of the wafer through a reinforcement ring curing adhesive, the outer edge of the reinforcement ring has the same shape and size as the outer edge of the wafer and the outer edge of the reinforcement ring is aligned with the outer edge of the wafer in the axial direction of the wafer, and the upper end face of the reinforcement ring is parallel to the upper surface of the wafer.

[0007] The wafer protection structure according to the embodiment of the present invention can effectively prevent the wafer from being deformed and damaged, improve the yield rate of finished products, reduce material waste and cost burden, and has other advantages.

[0008] In addition, the wafer protection structure according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the reinforcement ring curing adhesive is a debondable curing adhesive.

[0010] According to one embodiment of the present invention, the wafer protection structure also includes a carrier, the lower surface of the wafer is bonded to the upper surface of the carrier by carrier curing glue so that the wafer and the carrier are combined into a bonding sheet, and the reinforcement ring is located on the upper surface of the wafer.

[0011] According to one embodiment of the present invention, when at least one of the reinforcement ring curing adhesive and the carrier curing adhesive is a debonding curing adhesive and both the reinforcement ring curing adhesive and the carrier curing adhesive are debonding curing adhesives, the debonding methods of the reinforcement ring curing adhesive and the carrier curing adhesive are different.

[0012] According to an embodiment of the present invention, the debondable curing adhesive comprises one of a laser curing adhesive, a thermal curing adhesive, a water-thermal curing adhesive and a chemical curing adhesive.

[0013] According to one embodiment of the present invention, the thickness of the wafer is less than or equal to 100 microns and the diameter is greater than or equal to 150 mm; and / or the radial width of the reinforcement ring is 1 mm-3 mm and the axial thickness is 5 mm-15 mm.

[0014] According to an embodiment of the present invention, the reinforcement ring is a glass material piece, a metal material piece or a polyethylene material piece.

[0015] According to an embodiment of the second aspect of the present invention, a wafer processing method is provided, the wafer processing method comprising the following steps:

[0016] Providing a bonding sheet, the bonding sheet comprising a wafer and a carrier, the wafer and the carrier being bonded and connected by carrier curing adhesive;

[0017] Polishing and thinning the wafer;

[0018] Select a reinforcement ring whose outer edge has the same shape and size as the outer edge of the wafer, and apply reinforcement ring curing glue on the reinforcement ring;

[0019] Aligning the outer edge of the reinforcement ring with the outer edge of the wafer, and pressing the reinforcement ring onto the thinned wafer;

[0020] The reinforcement ring curing adhesive is cured.

[0021] The wafer processing method according to the embodiment of the present invention can effectively prevent the wafer from being deformed and damaged, improve the yield rate of finished products, reduce material waste and cost burden, and has other advantages.

[0022] According to one embodiment of the present invention, after curing the reinforcement ring curing adhesive, the following steps are also included:

[0023] The reinforcement ring curing adhesive is subjected to a debonding process.

[0024] According to one embodiment of the present invention, after curing the reinforcement ring curing adhesive, the following steps are also included:

[0025] The carrier curing adhesive is subjected to a debonding process.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 is a schematic structural diagram of a wafer protection structure according to an embodiment of the present invention.

[0029] Figure 2 It is a partial process schematic diagram of a wafer processing method according to an embodiment of the present invention.

[0030] Figure 3 It is a partial process schematic diagram of a wafer processing method according to an embodiment of the present invention.

[0031] Figure 4 It is a partial process schematic diagram of a wafer processing method according to an embodiment of the present invention.

[0032] Figure 5 It is a partial process schematic diagram of a wafer processing method according to an embodiment of the present invention.

[0033] Figure 6 is a flow chart of a wafer processing method according to an embodiment of the present invention.

[0034] Reference numerals: wafer protection structure 1 , wafer 10 , reinforcement ring 20 , reinforcement ring curing adhesive 30 , carrier 40 , carrier curing adhesive 50 . DETAILED DESCRIPTION

[0035] This application is based on the inventor's discovery and understanding of the following facts and problems:

[0036] The wafers in the related technology, especially the large-size wafers that are thinned to less than 100 microns and have a diameter greater than 150 mm, on the one hand, the crystal structure strength of the wafer itself is relatively fragile, and it is easily affected by external forces such as vibration and collision during transportation. Slight vibrations may also cause scratches or microcracks on the surface of the wafer. Moreover, the larger the size of the wafer, the greater its own weight and inertia, and the more likely it is to be damaged. On the other hand, it is inevitable that stress will be introduced into the wafer during the thinning process, which can easily cause the wafer to warp, reduce the wafer strength, and crack. In the subsequent processing process, cracks are easily generated in the stress concentration area when it is subjected to slight external force impact or temperature changes. This leads to a low yield of finished wafers and greatly increases the material waste and cost burden in the production process.

[0037] Specifically, some wafers in the related technology use a positioning ring with high structural strength to stick on the wafer to position the wafer. The outer diameter of the positioning ring is larger than the outer diameter of the wafer, and the outer edge of the positioning ring protrudes radially outward from the outer edge of the wafer, which can prevent external forces in a specific direction from directly acting on the edge of the wafer, thereby protecting the edge of the wafer to a certain extent.

[0038] However, it can only be used for positioning and protecting wafers under specific support tooling and specific processes, and is not suitable for wafer protection in other scenarios.

[0039] After extensive research, the inventor of this application found that the edge of the wafer is weaker than the inside, and the crack will gradually extend from the edge of the wafer to the inside. Since the positioning ring in the related art is annular and the outer diameter is larger than the outer diameter of the wafer, the positioning ring and the wafer are larger than the size of the wafer alone. On the one hand, the positioning ring further increases the force arm of the wafer, and because the positioning ring is annular, the force of the positioning ring cannot be well transmitted to the middle of the wafer. Although the radial external force will not directly act on the edge of the wafer, the external force acting on the positioning ring is more likely to generate stress on the edge of the wafer. Moreover, the outer edge of the positioning ring is not flush with the outer edge of the wafer, and the external force is more likely to act directly on the positioning ring. Moreover, because the positioning ring is annular, the wafer is unevenly stressed, which makes the wafer itself more susceptible to damage. On the other hand, the increased size further increases the difficulty of storing and transporting the wafer.

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] The wafer protection structure 1 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0044] like Figure 1-Figure 6 As shown, the wafer protection structure 1 according to the embodiment of the present invention includes a reinforcement ring 20 .

[0045] The reinforcement ring 20 is bonded to the upper surface of the wafer 10 (the up and down directions are shown by the arrows in the figure) through the reinforcement ring curing glue 30. The outer edge of the reinforcement ring 20 has the same shape and size as the outer edge of the wafer 10 and is aligned with the outer edge of the wafer 10 in the axial direction of the wafer 10. The upper end face of the reinforcement ring 20 is parallel to the upper surface of the wafer 10.

[0046] It should be understood here that the “ring” in the “reinforcement ring 20 ” should be understood in a broad sense, and the reinforcement ring 20 can be in a circular ring shape or in other closed loop shapes.

[0047] According to the wafer protection structure 1 of the embodiment of the present invention, by setting a reinforcement ring 20 on the edge of the wafer 10, the reinforcement ring 20 can be used to improve the structural strength of the edge of the wafer 10, and the reinforcement ring 20 can be used to prevent the wafer 10 from being deformed and damaged under the action of stress and external force. Compared with the wafer in the related art, it can effectively avoid the edge collapse, fragmentation and other phenomena of the thinned large-size wafer during the wafer picking, subsequent semiconductor processing, transportation and packaging processes, effectively improve the low yield of the wafer finished product, and greatly reduce the material waste and cost burden in the production process.

[0048] Furthermore, by making the outer edge of the reinforcement ring 20 the same shape and size as the outer edge of the wafer 10 and aligning the outer edge of the reinforcement ring 20 with the outer edge of the wafer 10 in the axial direction of the wafer 10, after the reinforcement ring 20 is set, the outer diameter of the whole formed by the reinforcement ring 20 and the wafer 10 is equal to the original diameter of the wafer 10. Compared with the method of setting a positioning ring with an outer diameter larger than the outer diameter of the wafer in the related art, on the one hand, the reinforcement ring 20 will not increase the force arm of the wafer, and the external force acting on the reinforcement ring 20 will not generate additional stress on the edge of the wafer. Moreover, the outer edge of the reinforcement ring 20 is flush with the outer edge of the wafer 10, and the external force will act on the reinforcement ring 20 and the wafer 10 at the same time, so that the wafer is subjected to more uniform force, making it less likely for the wafer 10 to be deformed or damaged due to external force and stress. On the other hand, the reinforcement ring 20 will not increase the size of the wafer 10, and the wafer 10 can be transported in the original storage method without increasing the difficulty of storage and transportation of the wafer 10.

[0049] In addition, by making the upper end surface of the reinforcement ring 20 parallel to the upper surface of the wafer 10 , the force directions of the reinforcement ring 20 and the wafer 10 can be consistent, thereby ensuring the protective effect of the reinforcement ring 20 on the edge of the wafer 10 .

[0050] Therefore, the wafer protection structure 1 according to the embodiment of the present invention has the advantages of being able to effectively prevent wafer deformation and damage, improve finished product yield, and reduce material waste and cost burden.

[0051] The wafer protection structure 1 according to a specific embodiment of the present invention is described below with reference to the accompanying drawings.

[0052] In some specific embodiments of the present invention, Figure 1-Figure 6 As shown, the wafer protection structure 1 according to the embodiment of the present invention includes a wafer 10 and a reinforcement ring 20 .

[0053] Advantageously, the reinforcement ring curing adhesive 30 is a debondable curing adhesive. In this way, when a separate wafer 10 is needed, the wafer 10 can be separated from the reinforcement ring 20 by debonding. For example, if a separate wafer 10 is needed or the reinforcement ring 20 needs to be removed in subsequent processing or packaging, the reinforcement ring curing adhesive 30 can be debonded to separate the wafer 10 from the reinforcement ring 20.

[0054] In addition, the reinforcing ring 20 after debonding can be reused to further save costs.

[0055] Figure 1 1 shows a wafer protection structure 1 according to some examples of the present invention. Figure 1 As shown, the wafer protection structure 1 also includes a carrier 40, and the lower surface of the wafer 10 is bonded to the upper surface of the carrier 40 through a carrier curing adhesive 50 so that the wafer 10 and the carrier 40 are combined into a bonding sheet (the up and down directions are shown by the arrows in the figure), and the reinforcement ring 20 is located on the upper surface of the wafer 10. In this way, it is convenient to perform a bonding and thinning process on the wafer 10, and the carrier 40 can further improve the structural strength of the wafer 10, and it is convenient to position and transfer the wafer 10 through the carrier 40.

[0056] Specifically, the reinforcing ring curing adhesive 30 and the carrier curing adhesive 50 may be light curing adhesive or heat curing adhesive. The carrier 40 may be a glass sheet, a silicon sheet or a flexible polymer film.

[0057] Optionally, at least one of the reinforcement ring curing adhesive 30 and the carrier curing adhesive 50 is a debondable curing adhesive and when both the reinforcement ring curing adhesive 30 and the carrier curing adhesive 50 are debondable curing adhesives, the debonding methods of the reinforcement ring curing adhesive 30 and the carrier curing adhesive 50 are different. In other words, the reinforcement ring curing adhesive 30 is a debondable curing adhesive and the carrier curing adhesive 50 is a non-debondable curing adhesive, or the reinforcement ring curing adhesive 30 is a non-debondable curing adhesive and the carrier curing adhesive 50 is a debondable curing adhesive, or the carrier curing adhesive 50 and the reinforcement ring curing adhesive 30 are both debondable curing adhesives and the carrier curing adhesive 50 and the reinforcement ring curing adhesive 30 have different debonding methods. For example, laser debonding curing adhesive, thermal debonding curing adhesive, water thermal debonding curing adhesive, chemical debonding curing adhesive. This can facilitate the separate separation of the carrier 40 and the reinforcement ring 20, avoiding the use of one debonding method that causes both curing adhesives to be separated.

[0058] For example, the carrier curing glue 50 can be a non-debondable curing glue, and the reinforcement ring curing glue 30 can be a laser debondable curing glue. In this way, when the reinforcement ring 20 needs to be separated separately, only the reinforcement ring curing glue 30 needs to be laser debonded. Alternatively, the carrier curing glue 50 can be laser debonded, and the reinforcement ring curing glue 30 can be chemically debonded. In this way, when the laser debonding process is used, the carrier curing glue 50 will be separated while the reinforcement ring curing glue 30 will not be separated. When the chemical debonding process is used, the reinforcement ring curing glue 30 will be separated while the carrier curing glue 50 will not be separated, so that the reinforcement ring 20 and the carrier 40 can be easily separated separately.

[0059] Specifically, the thickness of the wafer 10 is less than or equal to 100 micrometers and the diameter is greater than or equal to 150 millimeters. In this way, it is possible to reinforce relatively fragile large-sized wafers with smaller thickness and larger size.

[0060] Advantageously, the radial width of the reinforcement ring 20 is 1 mm to 3 mm and the axial thickness is 5 mm to 15 mm, which can ensure that the reinforcement ring 20 has sufficient structural strength and avoid the reinforcement ring 20 being too wide or too thick to generate additional stress.

[0061] Optionally, the reinforcement ring 20 is made of glass, metal or polyethylene, which can make the reinforcement ring 20 have a higher structural strength and improve the reinforcement effect of the reinforcement ring 20.

[0062] Specifically, the wafer 10 may be a silicon wafer, a lithium tantalate single crystal material piece, or a lithium niobate single crystal material piece.

[0063] The following describes a wafer processing method according to an embodiment of the present invention. The wafer processing method according to an embodiment of the present invention comprises the following steps:

[0064] Providing a bonding sheet, the bonding sheet comprising a wafer 10 and a carrier 40, the wafer 10 and the carrier 40 being bonded and connected by a carrier curing adhesive 50;

[0065] Polishing and thinning the wafer 10;

[0066] Select a reinforcement ring 20 whose outer edge has the same shape and size as the outer edge of the wafer 10, and apply a reinforcement ring curing glue 30 on the reinforcement ring 20;

[0067] Align the outer edge of the reinforcement ring 20 with the outer edge of the wafer 10, and press the reinforcement ring 20 onto the thinned wafer 10;

[0068] The reinforcement ring curing adhesive 30 is cured.

[0069] Specifically, the process of polishing and thinning the wafer 10 is as follows: Figure 2 As shown, the process of applying the reinforcing ring curing glue 30 on the reinforcing ring 20, aligning the outer edge of the reinforcing ring 20 with the outer edge of the wafer 10, and pressing the reinforcing ring 20 on the thinned wafer 10 is as shown in FIG. Figure 3 shown.

[0070] The polishing and thinning of the wafer 10 may include rough grinding, fine grinding, rough polishing and fine polishing.

[0071] The step of applying the reinforcement ring curing glue 30 on the reinforcement ring 20 may include applying a proper amount of curing glue using a brush, nano sponge, etc., or applying the curing glue by screen printing or the like.

[0072] According to the wafer processing method of an embodiment of the present invention, by setting a reinforcement ring 20 on the edge of the wafer 10, the reinforcement ring 20 can be used to improve the structural strength of the edge of the wafer 10, and the reinforcement ring 20 can be used to prevent the wafer 10 from being deformed and damaged under the action of stress and external force. Compared with the wafer in the related art, the thinned large-size wafer can be effectively prevented from having edge collapse, fragments, etc. during wafer picking, subsequent semiconductor processing, transportation and packaging, effectively improving the low yield of wafer products, and greatly reducing material waste and cost burden in the production process.

[0073] Furthermore, by selecting a reinforcement ring 20 whose outer edge is the same shape and size as the outer edge of the wafer 10 and aligning the outer edge of the reinforcement ring 20 with the outer edge of the wafer 10, after the reinforcement ring 20 is set, the outer diameter of the whole formed by the reinforcement ring 20 and the wafer 10 is equal to the original diameter of the wafer 10. Compared with the method of setting a positioning ring with an outer diameter larger than the outer diameter of the wafer in the related art, on the one hand, the reinforcement ring 20 will not increase the force arm of the wafer, and the external force acting on the reinforcement ring 20 will not generate additional stress on the edge of the wafer. Moreover, the outer edge of the reinforcement ring 20 is flush with the outer edge of the wafer 10, and the external force will act on the reinforcement ring 20 and the wafer 10 at the same time, so that the wafer is subjected to more uniform force, making it less likely for the wafer 10 to be deformed or damaged due to external force and stress. On the other hand, the reinforcement ring 20 will not increase the size of the wafer 10, and the wafer 10 can be transported in the original storage method without increasing the difficulty of storage and transportation of the wafer 10.

[0074] Therefore, the wafer processing method according to the embodiment of the present invention has the advantages of being able to effectively prevent wafer deformation and damage, improve finished product yield, and reduce material waste and cost burden.

[0075] Furthermore, if Figure 4 As shown, after the reinforcement ring curing glue 30 is cured, the following step is also included: debonding the reinforcement ring curing glue 30. In this way, the reinforcement ring 20 can be separated from the wafer 10, so as to obtain a separate wafer or remove the reinforcement ring 20.

[0076] Furthermore, if Figure 5 As shown, after the reinforcing ring curing adhesive 30 is cured, the following step is also included: debonding the carrier curing adhesive 50. In this way, the carrier 40 can be separated from the wafer 10, so as to obtain a separate wafer or remove the carrier 40.

[0077] The following describes wafer processing methods according to some specific embodiments of the present invention.

[0078] In some specific embodiments:

[0079] An 8-inch bonding wafer is selected, which includes a lithium tantalate wafer 10, an indestructible bonding photocuring adhesive (as a wafer carrier curing adhesive 50), and a silicon wafer (as a wafer carrier 40) from top to bottom. The bonding wafer is placed in a tray of a thinning machine, and a 1000-mesh grinding wheel is first used to quickly thin the lithium tantalate wafer 10 to less than 50 microns through rough thinning, and then a 3000-mesh grinding wheel is used to thin the wafer 10 to 30 microns through fine thinning. Finally, a polishing liquid is used to perform rough polishing and fine polishing on the wafer 10;

[0080] Select a metal ring (as the reinforcement ring 20) with the same edge size and shape as the wafer edge, with a width of 2mm and a height of 10mm. Place it in the screen printer with the smooth side facing up. After the reinforcement ring 20 is fixed, select a non-debondable light-curing glue (as the reinforcement ring curing glue 30) and apply a thin layer of glue on the surface of the metal reinforcement ring 20 by screen printing;

[0081] Place the reinforcement ring 20 on the polishing table, align the edge with the edge of the wafer 10, control the lowering height of the wafer 10 until the two are in contact, and then continue to lower it by 1mm to make the reinforcement ring 20 and the wafer 10 in close contact. After 10s, raise the polishing plate to achieve bonding between the reinforcement ring 20 and the thinned wafer 10.

[0082] The sample is taken out and transferred to a light curing device, and the sample is irradiated with ultraviolet light for 1 minute for curing, so as to cure the reinforcement ring curing glue 30.

[0083] In some other specific embodiments:

[0084] An 8-inch bonding wafer is selected, which includes a lithium tantalate wafer 10, an indestructible bonding photocuring adhesive (as a wafer carrier curing adhesive 50), and a silicon wafer (as a wafer carrier 40) from top to bottom. The bonding wafer is placed in a tray of a thinning machine, and a 1200-mesh grinding wheel is first used to quickly thin the lithium tantalate wafer 10 to less than 60 microns through rough thinning, and then a 4000-mesh grinding wheel is used to thin the wafer 10 to 20 microns through fine thinning, and finally a polishing liquid is used to perform rough polishing and fine polishing on the wafer 10;

[0085] Select a glass ring (as the reinforcement ring 20) with the same edge size and shape as the edge of the wafer 10, with a width of 2mm and a height of 10mm. Place it in the screen printer with the smooth side facing up. After the reinforcement ring 20 is fixed, select laser photocuring glue (as the reinforcement ring curing glue 30) and apply a thin layer of glue on the surface of the metal reinforcement ring 20 by screen printing;

[0086] Place the reinforcement ring 20 on the polishing table, align the edge with the edge of the wafer 10, control the lowering height of the wafer 10 until the two are in contact, and then continue to lower it by 1mm to make the reinforcement ring 20 and the wafer 10 in close contact. After 10s, raise the polishing plate to achieve bonding between the reinforcement ring 20 and the thinned wafer 10.

[0087] The sample is taken out and transferred to a light curing device, and the sample is irradiated with ultraviolet light for 1 minute for curing, and the reinforcing ring curing glue 30 is cured;

[0088] The sample is transferred to the debonding machine for laser debonding. The laser power is set to 3W. The laser beam is focused on the bonded sample and the reinforcement ring 20 area is scanned. The light-cured adhesive loses its adhesiveness after the laser beam scans. The silicon carrier 40 is fixed, and after the upper glass reinforcement ring 20 is removed, the residual adhesive on the surface of the wafer 10 is cleaned with acetone and alcohol.

[0089] In some other specific embodiments:

[0090] An 8-inch bonding sheet is selected, which includes a lithium tantalate wafer 10, a laser photocuring adhesive (as a carrier curing adhesive 50), and a glass sheet (as a carrier 40) from top to bottom. The bonding sheet is placed in a tray of a thinning machine, and the lithium tantalate wafer 10 is firstly thinned to less than 50 microns by rough thinning using a 1000-mesh grinding wheel, and then the wafer 10 is thinned to 15 microns by fine thinning using a 5000-mesh grinding wheel, and finally the wafer 10 is rough-polished and fine-polished using a polishing liquid;

[0091] Select a glass ring (as the reinforcement ring 20) with the same edge size and shape as the wafer edge, with a width of 2mm and a height of 10mm. Place it in the screen printer with the smooth side facing up. After the reinforcement ring 20 is fixed, select a non-debondable light-curing glue (as the reinforcement ring curing glue 30) and apply a thin layer of glue on the surface of the reinforcement ring 20 by screen printing;

[0092] Place the ring on the polishing table, align the edge with the edge of the wafer 10, control the lowering height of the wafer 10 until the two are in contact, and then continue to lower it by 1mm to make the reinforcement ring 20 and the wafer 10 in close contact. After 10s, raise the polishing plate to achieve bonding between the reinforcement ring 20 and the thinned wafer 10.

[0093] The sample is taken out and transferred to a light curing device, and the sample is irradiated with ultraviolet light for 1 minute for curing, and the reinforcing ring curing glue 30 is cured;

[0094] The sample is transferred to the debonding machine for laser debonding. The laser power is set to 3W. The laser beam is focused on the bonded sample and the entire wafer 10 area is scanned. The photocurable adhesive loses its adhesiveness after the laser beam scans. The glass carrier 40 is fixed, and after the upper lithium tantalate wafer 10 is removed, the residual adhesive on the surface of the wafer 10 is cleaned with acetone and alcohol.

[0095] Other structures and operations of the wafer protection structure 1 and the wafer processing method according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0097] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A wafer protection structure, characterized in that: include: A reinforcement ring, wherein the reinforcement ring is bonded to the upper surface of the wafer by a reinforcement ring curing adhesive, the outer edge of the reinforcement ring is the same in shape and size as the outer edge of the wafer, and the outer edge of the reinforcement ring is aligned with the outer edge of the wafer in the axial direction of the wafer, and the upper end face of the reinforcement ring is parallel to the upper surface of the wafer.

2. The wafer protection structure according to claim 1, characterized in that: The reinforcement ring curing adhesive is a debondable curing adhesive.

3. The wafer protection structure according to claim 1, characterized in that: It also includes a carrier, the lower surface of the wafer is bonded to the upper surface of the carrier through carrier curing glue so that the wafer and the carrier are combined into a bonding piece, and the reinforcement ring is located on the upper surface of the wafer.

4. The wafer protection structure according to claim 3, characterized in that: At least one of the reinforcement ring curing adhesive and the carrier curing adhesive is a debondable curing adhesive, and when both the reinforcement ring curing adhesive and the carrier curing adhesive are debondable curing adhesives, the debonding methods of the reinforcement ring curing adhesive and the carrier curing adhesive are different.

5. The wafer protection structure according to claim 4, characterized in that: The debondable curing adhesive includes one of a laser curing adhesive, a thermal curing adhesive, a water thermal curing adhesive and a chemical curing adhesive.

6. The wafer protection structure according to claim 1, characterized in that: The wafer has a thickness of less than or equal to 100 micrometers and a diameter of greater than or equal to 150 millimeters; and / or, The reinforcement ring has a radial width of 1 mm to 3 mm and an axial thickness of 5 mm to 15 mm.

7. The wafer protection structure according to claim 1, characterized in that: The reinforcement ring is made of glass, metal or polyethylene.

8. A wafer processing method, characterized in that: The following steps are involved: Providing a bonding sheet, the bonding sheet comprising a wafer and a carrier, the wafer and the carrier being bonded and connected by carrier curing adhesive; Polishing and thinning the wafer; Select a reinforcement ring whose outer edge has the same shape and size as the outer edge of the wafer, and apply reinforcement ring curing glue on the reinforcement ring; Aligning the outer edge of the reinforcement ring with the outer edge of the wafer, and pressing the reinforcement ring onto the thinned wafer; The reinforcement ring curing adhesive is cured.

9. The wafer processing method according to claim 8, characterized in that: After the reinforcement ring curing adhesive is cured, the following steps are also included: The reinforcement ring curing adhesive is subjected to a debonding process.

10. The wafer processing method according to claim 8, characterized in that: After the reinforcement ring curing adhesive is cured, the following steps are also included: The carrier curing adhesive is subjected to a debonding process.

Images